The present invention relates in general to remote control systems employing infrared light transmitters and receivers as a means of wireless communication, and particularly to a means to eliminate cross talk and interference between multiple transmitters.
Infrared transmitters and receivers are used extensively in indoor remote-control applications, such as in the remote control of audio and video entertainment systems. A typical infrared remote control system includes a single transmitter for the encryption, modulation, and transmission of control information, and a receiver for the reception, demodulation, and decoding of the transmitted signal, all for the control of a remote device. The transmitter is a remote, hand-held, wireless device that communicates with the receiver using infrared light signals. The receiver is connected electronically to one or more devices.
A limitation of known infrared remote control systems is that the simultaneous use of more than one transmitter device in association with a single receiver can result in cross-talk or interference between the transmitted signals, adversely affecting the ability of the receiver to implement properly the desired control function.
One solution to the problem is to stagger the data within each signal sent by the transmitters. The staggering of data allows reception of the signals substantially simultaneously with each other without data interference. However, data is encoded in order to preserve it during transmission, then decoded via decoding means such as look-up tables before transmission to the device. The look-up table requires added memory, added processing steps, and added time before the proper signal is finally directed to the device.
Accordingly, what is needed is a multiple transmitter, single receiver combination that requires a minimum amount of memory, fewer processing steps, and less time for operation than is presently available.